Table Of ContentNotalepid. 27 (1): 33^0 33
Blastodacna libanotica Diakonoff, 1939 - a pest on pear in
Turkey (Agonoxenidae)
Sjaak (J.C.) Koster1 Hikmet Özbek2 Irfan Aslan2 & Twan (A.L.M.) Rutten3
, ,
1 National museum ofNatural History Naturalis, PO Box 9517, 2300 RA Leiden, Netherlands; e-mail:
[email protected]
2 Atatürk University, Faculty ofAgriculture, Department ofPlant Protection, 25240 Erzurum, Turkey;
e-mail: [email protected]
3 Institute ofPlant Genetics and Crop Plant Research, Corrensstrasse 3, 06466 Gatersleben, Germany;
e-mail: [email protected]
Abstract.BlastodacnalibanoticaDiakonoff, 1939 (Agonoxenidae)isrecordedforthefirsttimetodam-
age pear trees (Pyrus sp.) during the larval stage. The observation has been made in Oltu, district of
Erzurumprovince(Turkey).The larvaemakegalls intheyoung shoots. Smalltreesdonot surviveheavy
infestationwiththispest. Thebiology is discussedandthe external characters ofthe moth andthe male
and female genitalia, as well as the immature stages, are illustrated.
Key words. Blastodacna,Agonoxenidae,lifehistory,taxonomy,pestspecies,Pyrus,Turkey,Palaearctic.
Introduction
Moths (Lepidoptera) can have an enormous impact on agriculture, forestry and stored
products. Many species can cause severe damage to fruit and crops. For example, in
the familyTineidae, the larvae ofthe clothes moths Trichophaga tapetzella (Linnaeus,
1758) and Tineola bisselliella (Hummel, 1823) are well known to feed indoors on
manufactured goods of animal origin such as wool and hair. In the family
Oecophoridae the larvae of Hofmannophila pseudospretella (Stainton, 1849) and
Endrosis sarcitrella (Linnaeus, 1758) feed on dead animal and vegetable matter, and
can be harmful to stored products and museum collections. In the Pyralidae the
species of Ephestia Guenée, 1845 and Cadra Walker, 1864 are notorious for the
damage to stored products; and several other species of the subfamily Phycitinae
canbe harmful to fruit and coniferous trees (Baker 1983). However, the largest group
of species that can influence our way of life belong to the Tortricidae. More than
400 species ofthis family attack crops and fruit or cause severe damage to deciduous
&
and coniferous trees (van der Geest Evenhuis 1991). In the rather small family
Agonoxenidae, Haplochrois theae (Kusnetsov, 1915) is a serious pest ofthe tea plant.
The genus Blastodacna Wocke, 1876 belongs to the same family, and Blastodacna
atra (Haworth, 1828) has been reported as a pest on apple {Malus sp.) (Miles 1930;
Balachowsky 1934). The larvae ofBlastodacna, from the few species of which the
immature stages have been described, live in twigs or fruits of woody Rosaceae.
Pupation takes place in a cocoon in the feeding place or in crevices of the bark of
the food plant. The genus has a Holarctic distribution, but most species have
been described from the Palaearctic region. Here we report for the first time damage
caused by a second species of that genus, B. libanotica Diakonoff, 1939 on pear
and wild pear.
©Notalepidopterologica,28.06.2004,ISSN0342-7536
34
Kosteretal.: Blastodacna libanotica
Material and Methods
Galls caused by B. libanotica were first found in August 2001 on the twigs ofwild
pear(Pyrus elaegrifolia) on aroadside 4 kmwest ofOltu, inthe province ofErzurum,
Turkey (Figs. 1, 2). The city ofOltu is locatednearatributary ofthe CoruhRiver. Thme
observations were made along a narrow valley, starting from an altitude of2000
m
and descending to 700 over a distance ofmore than 100 km. Pear plantations can
m
be found in this valley from the Black Sea coastup to 1400 altitude. Although wild
pear trees are abundant up to 2200 m, infested trees were only found up to 1600 m;
m
trees higherup thanthis showedno infestation. Between 1000-1400 cultivatedpear
m
trees are not very abundant, but wild pear trees are more common. Below 1000
there are many orchards growing apple, pear and other fruit in mixed orchards. In the
summer of 2003 a survey was conducted to detect the presence ofthis insect along
the valleys ofUzundere, Tortum and Ispirwhich are fruit-growing areas. Itwas found
that the trees in these locations were also infested with this pest, but the population
density was very low compared with that in Oltu. Both cultivated and wild pear trees
are infested, but small wild pears much more heavily so than bigger trees. The dam-
age caused by this pest resulted in the death ofseveral small wild pear trees.
29 and 4c? ofB. libanotica have been reared from Turkey, Erzurum, Oltu-Subatik,
1300 m, 4-12.iii.2002, leg. H. Özbek. The immature stages ofthis species have not
been depicted before. Detailed pictures ofthe larvae and pupae were prepared with a
SEM operated by Twan Rutten. For SEM observations, larvae and pupae were dehy-
drated in an ethanol series of50%, 70%, 90% and 100% (2x), each step lastingat least
15 minutes. Samples were then critical point dried in a Bal-Tec CPD030 critical point
dryer(Bal-TecAg, Liechtenstein). Dried samples were attachedto analuminium sam-
ple block and gold coated in an Edwards S150B sputter coater (Edwards high vacu-
um inc., Crawley, West Sussex, UK). Examination of the specimens and digital
recordings were made in a Hitachi S4100 SEM (Hisco Europe, Ratingen, Germany)
and saved as tif-files. Due to the dimensions oflarvae and pupae, several recordings
were required to produce overview images. The complete picture was obtained by
subsequent editing in Photoshop 6.0.
Nota lepid. 27 (1): 33^0 35
Blastodacna libanotica Diakonoff, 1939
Diagnosis.The species ofthe genusBlastodacna
are small moths with a wingspan mainly of
9-15 mm, and have dark forewings with rather
conspicuous tufts ofraised scales. Blastodacna
libanotica (Fig. 3) canbe distinguished from the
other species in Europe and adjacent areas by
the rather large wingspan, 14-15 mm, and by
the forewing which has a white costal streak and
a white-outlined triangular mark beyond the
Fig. 3. Blastodacna libanotica Diakonoff, middle. For more detailed descriptions of the
9(watercolourJ.C.Koster). adults and me male and female genitalia 0f
Blastodacna species fromthe western Palaearctic
region see Koster& Sinev (2003). Fromthe four
species ofBlastodacna known from the eastern
Palaearctic region, B. pyrigalla (Yang, 1977), known from China and Korea, is very
closely related to B. libanotica or possibly even conspecific.
Description of immature stages. Ovum. Light brown (Talhouk 1948). This author
describes the eggs as light brown, but his observation is from shrunken eggs in a
rearing case which never hatched. In comparison with other species ofBlastodacna,
the eggs ofB. atra and B. hellerella are translucent white, later they become opaque
and yellowish, and finally brownish (Miles 1930, 1932).
Larva. Rather short and fat. Head dark brown with six conspicuous whitish ocelli
on each side in an oval grouping (Fig. 4); mandibles (Fig. 5) light brown; fronto-
clypeus whitish. Prothoracic plate dark brown, mixed whitish and divided dorsally;
anal plate small, dark brown. Thoracic legs (Fig. 6) laterally with a dark brown
posterior band on each segment. Abdomen bone-white; abdominal prolegs (Fig. 7)
and anal prolegs (Fig. 8) whitish, a dark brown band above both anal prolegs. Length
5.5-6.5 mm. The larvae of B. atra and B. hellerella vary from greyish white to
brownish pink, are more slender and have longer setae (Miles 1930, 1932).
Pupa (Figs. 9-1 1). Palebrown, anteriorandposteriorparts darker. Length 5.5-6 mm.
Wing sheaths rather short, reaching halfway along abdominal segment six. This is in
contrast with B. atra, where the wing sheaths almost reach the end ofthe abdomen
(Réal 1966). Ventrally on the combined ninth and tenth segment are two long leg-like
protrusions at an angle of 30°-60° with the abdomen (Fig. 12). Anteriorly they are
densely covered with hooked setae (Fig. 13). Cremaster absent.
Life history. Oviposition takes place in spring. Despite several attempts, oviposition
was not observed. B. pyrigalla lays its eggs around the base ofthe buds ofPyrus sp.,
and, afterhatching, the young larvae move to a new twig and bore into the stem (Park
1986). The B. libanotica female also prefers to lay her eggs on new shoots. This was
ascertained by attaching infected twigs to a small wild pear tree in early spring of
2002. A total of33 galls were made by the larvae from those infected twigs. All but
two ofthe galls were found in the young shoots. The remaining two were made in
shoots ofthe previous year's growth.
36
Kosteretal.: Blastodacna libanotica
Figs. 4-7. Features ofthe larva ofBlastodacna libanotica Diakonoff(SEM photos byA.L.M. Rutten).
4. Head ofthe larva (scale bar 200um). 5. Mouthparts ofthe larva showing the mandibles (scale bar
40 urn). 6. Thoracic legs ofthe larva (scale bar 90 um). 7. Abdominal prolegs ofthe larva (scale bar
200 urn).
The larva makes a gallery in a thin twig in summer and early autumn. The gallery
starts inwards at an angle ofabout 30° to the long axis ofthe twig, is then directed
upward, later again in an angle of about 30° (Fig. 14). This activity causes the
mm mm
development ofan elongate gall 11.5-13.5 in length and 7.3-8.6 in width.
The gall is more or less constricted in the middle and with a rounded opening at
the lower end (Fig. 15). Prior to pupation the larva enlarges the exit-hole and
smoothes a circular area around its perimeter. Pupation takes place inside the gall
at the end ofautumn (Fig. 16).
There can be more than one gall in a twig. All exit-holes were also in the lower part
ofthe galls, except in united galls (Fig. 17), but the polished circle around it was not
always visible. From 15 July several galls were opened every two days to follow
the process ofthe construction ofthe exit-holes and the stage towards pupation. On
15 July very small holes could already be observed by the extrusion ofsome grains
ofsawdust. Four days later they had been enlarged to maximum size. By 30 July all
dissected galls contained larvae in the last instar, and after this date pupae were also
Notalepid. 27(1): 33-40 ^7
8
1 90(im 1
Figs. 8-13. Features ofthe pupa ofBlastodacna libanotica Diakonoff(SEM photos byA.L.M. Rutten).
8.Anal prolegs ofthe larva (scale bar 90 urn). 9. Pupa in dorsal view (scale bar 500 urn). 10. Pupa in
lateral view(scalebar500 urn). 11. Pupa in ventral view (scalebar500 urn). 12. Leg-likeprotrusions at
posterior end ofpupa (scale bar 200 urn). 13. Hooked setae on the leg-like protrusions with remains of
silkofthe cocoon (scale bar40 urn).
found. On 10 September almost all ofthe dissected galls containedpupae. The larvae,
as well as the pupae, were found with their heads directed towards the exit-holes.
The larva constructs a cocoon inthe lowerpart ofthe gallery inwhich the pupa hiber-
nates. Both abdominal protrusions are firmly embedded into the silk ofthe cocoon,
and hold the pupa in place during emergence ofthe adult.
38 Kosteretal.: Blastodacna libanotica
Fig. 14-17. Features ofthe galls ofBlastodacna libanotica Diakonoff(photos H. Özbek). 14. Longi-
tudinal section ofthe gall with the upward part ofthe gallery. 15. Gall with exit-hole (scalebarlO mm).
16. Longitudinal section ofthe gall with the pupa, its head directedtowardthe exit-hole. 17.Twigswith
united galls.
Nota lepid. 27 (1): 33^0 39
Adults appeared from 25 April to 10 May. In Lebanon, emergence ofthe adults had
already started in February and lasted until May. The later appearance of adults in
Turkey is possibly due to different latitude and the higher altitude.
Host plant. Pyrus sp. (Rosaceae), butTalhouk (1948) also reported a few galls on
hawthorn {Crataegus sp.). The hostplant ofthe sibling B. pyrigalla is also pear, but it
has also been found on peach {Prunus persica) and persimmon {Diospyros kaki,
Ebenaceae) (Park 1986).
Parasites. No parasites were found in the Turkish material. Talhouk (1948) men-
tioned the rearing ofseveral specimens ofPimplinae (Hymenoptera: Ichneumonidae)
from distorted galls, later reported as belonging to the genus Lissonota Gravenhorst,
1829 (Herting & Simmonds 1975).
Distribution. B. libanotica has been described from specimens reared from galls on
pear found inAley, Lebanon in 1933 (Diakonoff 1939). In 1938 and following years,
galls were also found in Abaydieh, Lebanon (Talhouk 1948). The first record for
Turkeywas made by Koster & Sinev (2003), this with reference to a female specimen
from Gebse, 50 km east ofIstanbul, collected by Glaser in 1969. Some authors also
mention Syria, referring to the original description (Diakonoff 1939), but in those
days Lebanon was a part of Syria. It is remarkable that this species on wild and
cultivatedpearhas so far onlybeenrecorded from Lebanon and easternTurkey. Since
it occurs as a pest on economically important plants, surveys should be conducted
to determine possible infestation in other parts of the country, as well as in other
Middle East countries.
Conclusion. B. libanotica is here shown to be apest on wild and cultivatedpeartrees
inTurkey forthe firsttime. It canbe regarded as aminorpest inthe fruit growing area
along the valleys ofOltu, Uzundere, Tortum, and Ispir. However, it has been observed
that wild pear trees, particularly the small ones, were more attractive than the culti-
vated pear trees. Heavily infested branches ofsome wild pear trees were completely
withered, which could cause the death ofsmall trees. It is possible that infested wild
pear trees will act as a reservoir of infestation for future pear plantations in these
areas. When the main shoot ofcultivated trees is infested, its growth is retarded and
this induces an increased development ofthe lateral shoots.
Acknowledgements
WillyDe Prins (Antwerp, Belgium) is acknowledgedforpointingoutthe existence oftheTurkishmate-
rialto Sjaak Köster. We also thank Erik vanNieukerken (Leiden, Netherlands) forhis comments on an
earlierdraftofthemanuscript andJohn Langmaid (Southsea, U.K.) forcorrecting the English text.
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